The present invention relates to a vehicle fuel rail assembly for an internal combustion engine having an improved fuel delivery system and an improved liquid fuel retention therein.
In warm climates, vehicle engine temperatures may exceed 200 degrees Fahrenheit or greater. At such high temperatures, fuel contained within the fuel rail system typically boils and evaporates. Elevated vapor pressure within the fuel rail system can provide the motive force to push fuel from the fuel rail to the chassis line back to the fuel tank. When a substantial portion of liquid fuel has been forced from the fuel rail system to the fuel tank, insufficient liquid fuel may be available to the injector cups to provide adequate fuel at start-up. As a result, such insufficient liquid fuel may cause the engine to require several seconds and/or multiple start up attempts to refill the fuel rail system sufficiently to start the engine.
Moreover, when fuel is delivered to a typical fuel rail system, the banks of the fuel rail are normally filled in series rather than in parallel. That is, the bank nearest in fluid communication with the fuel tank is typically filled first and then subsequent banks are filled. However, when a typical fuel rail is filled after a high temperature soak, engine problems may occur due to the uneven distribution of fuel within the fuel rail.